An ANSI schematic of the operation of the prior art R-10 magnet valve is given in FIG. 2. The R-10 magnet valve described below is manufactured and sold by Westinghouse Air Brake Technologies Corporation. The R-10 magnet valve consists of two two-way Air Flow Management Valves, one three-way Application Pilot Valve, and one three-way Release Pilot Valve. The operation cycle of the R-10 magnet valve is described below.
When the pilot valves are deenergized, a supply pressure from the reservoir enters the unit and pilots the application valve open, and the supply pressure flows to a brake cylinder.
When the application pilot is energized, thereby restricting the application valve to the choked port, the brake cylinder pressure is sustained.
When the release pilot is energized, the release pilot pressure is exhausted and the release valve is forced open by the brake cylinder pressure. The choked supply port flows to exhaust also.
When the application pilot is deenergized and while the release pilot remains energized, the application pilot pressure is exhausted and the application valve opens. This allows the supply pressure to flow unrestricted through the exhaust port.
An ANSI schematic of the operation of the prior art N-7-D Magnet Valve is given in FIG. 3. The N-7-D magnet valve described below is also manufactured and sold by Westinghouse Air Brake Technologies Corporation. The N-7-D magnet valve consists of one two-way Air Flow Management Valve, one three-way Air Flow Management Valve, one three-way Application Pilot Valve, and one three-way Release Pilot Valve. The operation cycle of the N-7-D Magnet Valve is described below.
With the pilot valve deenergized, a supply pressure flows directly into the brake cylinder from the reservoir. Pilot pressure is supplied independently.
With the application pilot energized, it closes the supply pressure off from the brake cylinder and brake cylinder pressure exhausts.
With the release pilot energized, the exhaust port is closed off from the brake cylinder, thus holding brake cylinder pressure constant.
With the application pilot deenergized while the release pilot remains energized, the application pilot pressure is exhausted, causing the application valve to close off exhaust from the brake cylinder, thus allowing supply pressure to flow to the brake cylinder.